1. Field of the Invention
The present invention is generally directed to apparatus and method for detecting venous obstruction. More particularly, but not by way of limitation, the invention is directed to apparatus and method for detecting DVT in a patient by measuring blood volume, temperature, calf size and other clinical indications.
2. Related Art
There exist many methods for detection of obstruction in a human's circulatory system. Depending upon which part of the circulatory system is examined, a particular method may or may not lend itself as well to detecting obstructions. Methods employing invasive, i.e., surgical techniques, are a last resort due to their inherent severity and limitations in repeated use.
Non-invasive devices have hence been preferred in the diagnosis of venous obstruction. Ultrasonic devices have been used to study venous thrombosis in the deep veins, but are limited in that these require highly skilled operators, thus rendering subjective uncertainty in their resulting diagnosis.
Other devices measure arterial elasticity to determine whether sclerosis exists in the artery. Such devices have employed photoelectric plethysmography to monitor the change in transmitted light intensity across tissues, such as fingers, to diagnose sclerosis.
Still others have used inflatable cuffs which wrap about a limb and measure diastolic and systolic pressure to detect peripheral arterial disease. Others have coupled cuffs with impedance plethysmography to detect atherosclerosis. Also, there has been use of light reflective rheography on the ankle for detection of chronic venous insufficiency.
Although there exist various apparatuses and methods of detecting venous and arterial irregularity, there remains a great need to improve apparatuses and methods for the detection of DVT. Specifically, the existing devices which detect DVT by measuring venous outflow such as impedance plethysmography or strain-gauge plethysmography, are not consistent from patient to patient, require highly developed operator skill, and are unable to detect chronic proximal DVTs or acute/chronic distal DVTs. The present invention, through the use of multiple risk factor analysis and artificial intelligence algorithms is able to overcome the shortcomings of the prior art devices and provide a significantly improved apparatus for detecting DVT.